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QUIET WITH A SLIGHT CHANCE OF FLARES: Solar activity is low, but one sunspot could break the quiet. AR2331 has a 'beta-gamma' magnetic field that harbors energy for M-class flares. NOAA forecasters estimate a 5% chance of such an eruption on April 27th. Solar flare alerts: text, voice.
VOLCANIC PLUME, COLORFUL SUNSETS: European MetOp satellites have been monitoring aerosols blasted into the atmosphere by Chile's Calbuco volcano on April 22nd. This 5-day movie shows a plume of sulfur dioxide spreading east from Chile to Brazil:
Credit: The Global Ozone Monitoring Experiment-2 (GOME-2) onboard MetOp-A and MetOp-B
The effect of this plume on Brazilian sunsets has been dramatic. Helio C. Vital of Rio de Janeiro reports: "Pushed by strong winds, aerosols from Calbuco reached Rio today (April 26) and produced an spectacular display of bright unusual colors across most of the western sky during evening twilight. The red-magenta glow lasted until an hour after local sunset."
This is what he saw:
As the sun set and the twilight faded, Jupiter and the Moon over Rio were surrounded by a distinctly purple hue.
Purple is one of the telltale signs of a volcanic sunset. Fine volcanic aerosols in the stratosphere scatter blue light which, when mixed with ordinary sunset red, produces a violet hue. But purple isn't the only thing to look for, says atmospheric optics expert Les Cowley. In addition, he advises, sky watchers in Chile and Brazil should "be alert for a very bright yellow twilight arch, fine cloud structure in the arch seen through binoculars, and long diffuse rays and shadows."
Stay tuned for updates from beneath the volcanic plume.
Realtime Space Weather Photo Gallery
THE BIGGEST THING ON THE SUN: An enormous filament of magnetism is snaking over the sun's northeastern limb. How big is it? If you placed one end on the Earth, the other end of the filament would extend past the orbit of the Moon. To illustrate the scale of this massive structure, Göran Strand of Östersund, Sweden, combined a picture he took of the filament on April 27th with an Earth-Moon ruler:
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The scale of the filament makes it an easy target for backyard solar telescopes. "I used a Lunt LS80," says Strand. "Otherwise the sun was quite calm, but this filament was very impressive through my solar telescope."
As Strand pointed out, today the sun is calm. This could soon change: Bushy solar filaments like the one currently on display often become unstable and erupt. Debris falling to the sun's surface can produce secondary explosions called Hyder flares--a type of flare that happens without an underlying sunspot.
SpaceWeather Realtime Photo Gallery
SPACE YEAST MAKES SPACE BREAD: Thought experiment: Suppose you flew a packet of baker's yeast high above Earth's surface, to the edge of space itself, and exposed the microbes to a blast of cosmic rays. Then you made some bread. How would it taste? "Delicious," reports Eileen Weingram of Highland Lakes, New Jersey, who actually did the experiment:
On March 17th, during the strongest geomagnetic storm of the current solar cycle, the students of Earth to Sky Calculus flew a Space Weather Buoy to the stratosphere. Along with radiation detectors and other sensors, the payload carried packets of brewer's and baker's yeast. En route to the stratosphere, the microbes experienced temperatures as low as -63 C and cosmic ray doses 40x Earth-normal.
To support the students' research, Eileen Weingram bought a packet of the baker's yeast. "It made a huge loaf of bread," she says. "Very yummy."
If this story whets your appetite, you can bake some "space bread" of your own. Packets of yeast are still available for only $49.95. Contact Dr. Tony Phillips to place your order--and let the baking begin! All sales support high altitude balloon flights to measure the effect of solar storms on Earth's atmosphere.
Realtime Meteor Photo Gallery
Realtime Aurora Photo Gallery
Realtime Comet Photo Gallery
Every night, a network of NASA all-sky cameras scans the skies above the United States for meteoritic fireballs. Automated software maintained by NASA's Meteoroid Environment Office calculates their orbits, velocity, penetration depth in Earth's atmosphere and many other characteristics. Daily results are presented here on Spaceweather.com.
On Apr. 27, 2015, the network reported 9 fireballs.
(9 sporadics)
In this diagram of the inner solar system, all of the fireball orbits intersect at a single point--Earth. The orbits are color-coded by velocity, from slow (red) to fast (blue). [Larger image] [movies]
Potentially Hazardous Asteroids (
PHAs) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding
new ones all the time.
On April 27, 2015 there were potentially hazardous asteroids.
Notes: LD means "Lunar Distance." 1 LD = 384,401 km, the distance between Earth and the Moon. 1 LD also equals 0.00256 AU. MAG is the visual magnitude of the asteroid on the date of closest approach. | The official U.S. government space weather bureau |
| The first place to look for information about sundogs, pillars, rainbows and related phenomena. |
| Researchers call it a "Hubble for the sun." SDO is the most advanced solar observatory ever. |
| 3D views of the sun from NASA's Solar and Terrestrial Relations Observatory |
| Realtime and archival images of the Sun from SOHO. |
| from the NOAA Space Environment Center |
| the underlying science of space weather |